Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Rewriting Life

Squeal Stopper

A material that expands when voltage is applied could silence an automobile’s brakes.

Brakes-even new ones-are plagued with the problem of squeal, a major cause of consumer complaint and warranty repairs. The exact cause is unclear, but according to one theory, the rotor and pads vibrate from the friction of rubbing together, creating a high-pitched screech that squeal suppression tactics such as replacing the pads don’t always cure. Ken Cunefare, a mechanical engineer at the Georgia Institute of Technology, says he has a better solution: a small cylinder housed inside each brake piston. The device holds several layers of a piezoceramic material that stretches when a voltage is applied across it. Every time the driver hits the brakes, a varying voltage is applied to the device, and the material grows or shrinks a few hundredths of a millimeter-changing the force with which it presses against the steel plate on the back of the brake pad. The pulsing pressure causes the brake to vibrate at a higher, inaudible frequency. Cunefare has done lab tests and is looking for a corporate partner to help him build a second-generation prototype that he could road-test on cars.

More from Rewriting Life

Reprogramming our bodies to make us healthier.

Want more award-winning journalism? Subscribe to Insider Online Only.
  • Insider Online Only {! insider.prices.online !}*

    {! insider.display.menuOptionsLabel !}

    Unlimited online access including articles and video, plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

/3
You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.